The present invention relates to a cup made of paper material comprising a fillable interior, which is formed by a conical sleeve and a bottom, whereby the bottom is attached with a bottom skirt essentially liquid-tight to the sleeve at the lower end of the interior, and whereby the sleeve comprises an outwardly formed lip at the upper end of the sleeve.
Cups of this type are applied with success in the field and used for example for the consumption of beverages. One-walled cups of the above named type are supported during stacking with their standing surfaces at the lower edge of the bottom skirt on the bottom of a cup of the same type. The bottom skirt and the bottom are stressed by the forces which occur during stacking.
It is an object of the present invention to improve the known cup.
This object has been achieved in accordance with the present invention in that the height of the lip is greater that the height of the bottom over the standing surface of the cup at the lower edge of the bottom skirt.
The increased height of the lip causes an advantageously changed appearance of the cup. In addition, the bottom skirt and the bottom are kept free of stress in an advantageous way when a number of cups are stacked together. It can be advantageously provided that the lip comprises a first and a second holding means, which support the cup during stacking against another cup of the same type. The first holding means is advantageously formed by an upper edge of the lip. The second holding means is advantageously formed by a lower edge of the lip.
A double-walled paper cup is known from German published patent application DE 10 2005 017 741 A1, in which the upper edge of the lip forms a first holding means. The second holding means is formed by a shoulder-shaped stacking stopper, which is assigned to the lip. An embodiment of this kind is not suitable for a one-walled cup. The outer sleeve is essential in order to achieve the advantageous stacking properties. The bottom and the bottom skirt of this cup are not subject to stress during stacking, the outer wall however is stressed in this case by the forces occurring during stacking.
In the case of the cup according to the present invention, the good stacking ability is independent of the presence of an outer sleeve. In an embodiment of the present invention it can be provided that the cup comprises an outer sleeve. If provided that a heat-insulating outer sleeve is arranged to the cup, this outer sleeve can be designed to a great extent as wished without influencing the stacking properties. The forces occurring during stacking simply are relayed within the lip. If an outer sleeve is provided, it is not stressed by the forces occurring during stacking.
The design of an optional heat-insulating outer sleeve can take any chosen form. The outer sleeve can, for example, be produced from synthetic, paper or composite material. In order to improve the insulating effect, the outer sleeve can also be corrugated, fluted, embossed or comprise a foamed coating. The outer sleeve can also be multilayered, for example a corrugated middle layer can be provided which is covered by a flat outer layer disposed thereon. As the cup according to the present invention can be stacked independently of the outer sleeve, the same cup can be simply combined in almost any way with a large variety of outer sleeves. Without altering the form and dimensions of the inner cup or of the lip, a variety of cups having different optical and haptical appearances can be created, as the outer appearance, as perceived by the user of the cup, is determined essentially by the design of the outer sleeve.
During the production process, the cup according to the present invention can be stacked at this stage in a secure and stable manner as a semi-finished product when the finished inner cup has to be stacked before the outer sleeve is applied in a subsequent process.
In the case of cups made of paper material, the bottom skirt is a very important element of the cup. The bottom skirt is necessary for joining the sleeve and the bottom. At least two material layers are disposed in thickness direction on top of one another, namely the material of the bottom and the material of the interior-defining sleeve. The bottom is advantageously pot-shaped, the open side of said bottom facing away from the filling opening of the cup. The at least two material layers are advantageously arranged along the wall of the pot-shaped bottom. It can be additionally provided, for example, that the sleeve is folded inwards around the material of the bottom, and that the bottom skirt consists of three or more material layers. The material of the bottom is glued or sealed to the material of the sleeve in the area of the bottom skirt, in order that it is liquid-tight for at least a certain time.
The term “paper material”, from which the bottom and the sleeve are made, includes various material, which comprise at least one layer of paper, paperboard or cardboard. In addition the material can comprise one or more layers made of synthetics and/or aluminium. It can also be provided that the paper material is waxed or coated, in order to provide a resistance against the liquid with which the cup is subsequently filled. The paper material is advantageously coated at least on the side facing the interior with a thin synthetic layer, preferably made of polyethylene. In contrast to purely synthetic material, the formability and in particular the ductibility of such paper material is limited. In the case of too great a deformation, the paper material itself, or a provided coating, may tear, so that the liquid-tight properties are impaired. The bottom skirt is therefore an essential design feature in the case of cups made of paper material and cannot be omitted, and care must be taken that the liquid tightness is not impaired in any way. The lip is, in contrast, significantly less critical as regards the liquid tightness. The lip is formed on the upper edge of the sleeve forming the interior, in that the sleeve is formed outwards and rolled in. The formed areas of the material of the sleeve lie after formation of the lip essentially on the outer side of the cup, which does not actually come into contact with the liquid to be filled. If a tear occurs in the coating of the sleeve during formation of the lip, this has virtually no effect on the liquid tightness of the cup.
It can be advantageous that the material of the sleeve in the area of the upper edge is heated up before and/or during the formation of the lip. Heating up can take place for example by means of blowing the sleeve with hot air, or by means of a heated forming tool. The temperature is advantageously so chosen that any synthetic layer present in the paper material does not reach its melting point, but rather just becomes somewhat softer.
With the lip according to the present invention, very stable stacks having a high number of cups can form, which do not wedge inside one another either when the stack is subjected to knocks or for example is set abruptly down on the ground.